Hissing TRV

[pilsbury]

New rads were fitted many months ago with new TRVs from screwfix. 5 in total. All were simply left fully open with no issues (number 5) but as the new kitchen tends to be a bit warmer I turned the TRVs on the 2 big kitchen rads down to 4. I then noticed a hissing sound at some points when the heating was on.

This is cured by moving the TRV setting slightly up or down. But then next time the heating comes on, the hissing is back. I just move the TRV setting slightly to cure again. Not really up for this daily routine. Still happens now if I leave them fully open on setting 5

The other rads where I haven’t moved the TRVs are fine. Why is this happening? I can merely guess in my limited knowledge they are starting to operate and shutting down a bit restricting the flow? Seems strange as the house is only about 21 degrees. Why does this happen now I’ve fiddled with them and didn’t before?

What’s the fix? New head? Please tell me not new valve!

 

[Dan Robinson]

Try opening your bypass a bit more or reducing the pump speed

 

[footprints]

Several of my TRV's do the same it's just the sound of water forced through a small gap, like clicking on heat up, not unusual at least it shows the valve is working.

 

[pilsbury]

Try opening your bypass a bit more or reducing the pump speed

You’ll have to forgive me..... opening the bypass a bit? You talking about the lock shield? I guess not.
Same for reducing pump speed. Not really got a clue on that.

 

[pilsbury]

Several of my TRV's do the same it's just the sound of water forced through a small gap, like clicking on heat up, not unusual at least it shows the valve is working.

Glad I’m not the only one, but what I don’t understand is why the others which are exactly the same don’t do this and the offending ones didn’t until I moved them.

Plus, why do they only do it when the rads are up to heat? I can’t see it being them operating. Set to 5 isn’t that meant to be approx 25degrees? My house is never near that.

 

[footprints]

When the rads are up to heat is when the gap is just closing so water is being forced through a tight gap.
The house temp has only a vague relationship to the temp at the valve head which is what the valve is sencing. A valve in a corner or behind a curtain or covered with knickers to dry ( depending on whether they are
M&S big pants or flimsys from Ann Summers) will feel hot and happy so shut down! A valve in a draught will be very slow to operate.

 

[pilsbury]

A valve in a corner or behind a curtain or covered with knickers to dry ( depending on whether they are
M&S big pants or flimsys from Ann Summers) will feel hot and happy so shut down!

So as I understand, I should only wear Anne summers knickers from now on? Glad to have finally sorted the issue.

 

[footprints]

 

[Ian H]

So as I understand, I should only wear Anne summers knickers from now on? Glad to have finally sorted the issue.

And keep you snake in your pants!!

 

[pilsbury]

And keep you snake in your pants!!

How on earth could I do that with some Anne summers skimpys? Tackle is going to be bursting out both sides..... a small price to pay for quiet TRVs.

 

[footprints]

You could Google posing pouch, but don't blame me for the results you might get!

 

[muggles]

As Dan suggested, your pump speed is too high so the velocity of water through the pipework and valves is too great. Turn it down and all should be well